Section 2BSection 2B

Standardized UnitsStandardized UnitsPages 100-112Pages 100-112

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Standardized Unit SystemsStandardized Unit Systems Metric system (SI)Metric system (SI)

SystSystèème Internationalme International

U.S. customary system (USCS)U.S. customary system (USCS) Roots from ancient Middle Eastern Roots from ancient Middle Eastern

civilizationscivilizations

Unit Conversions within systemsUnit Conversions within systems Unit Conversions between systemsUnit Conversions between systems

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U.S. Customary system – U.S. Customary system – LengthsLengths

page 101page 101

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U.S. Customary system – U.S. Customary system – WeightsWeights

page 102page 102

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U.S. Customary system – U.S. Customary system – VolumesVolumes

page 102page 102

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ExampleExample::

In the Kentucky Derby, horses race In the Kentucky Derby, horses race 10 10 furlongsfurlongs. How many . How many milesmiles is is this?this?

18 mile

10 furlongs1 furlong

1.25 miles

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Conversions within USCS

In 20,000 Leagues Under the Sea, does the title refer to an ocean depth?

3 .20,000 60,000 .

1

naut milesleagues naut miles

league

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[convert marine leagues to miles]

69046.6miles

6076.1 . 160,000 .

1 . 5280 .

ft milenaut miles

naut mile ft

Conversions within USCS

If 150 bushels of wheat are traded on one day, how many cubic inches are traded?

34 8 67.2150

1 1 1

pecks dry quarts inbushels

bushel peck dry quart

3322,560 in

International Metric SystemInternational Metric System

Invented in France, late 18Invented in France, late 18thth centurycentury Replace many customary units Replace many customary units

with a few basic unitswith a few basic units Simplify conversions by using a Simplify conversions by using a

base 10 systembase 10 system

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International Metric SystemInternational Metric System

The basic units are:The basic units are: metermeter (m) for length (m) for length kilogramkilogram (kg) for mass (kg) for mass secondsecond (s) for time (s) for time literliter (L) for volume (L) for volume

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Metric system - PrefixesMetric system - Prefixes

Moving between metric units requires shifting the decimal placeone to the right when going to the next smaller unit and one to theleft when going to the next larger unit.

(Example: 5.23 cm = 52.3 mm)

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ExamplesExamples

Convert Convert 19 decimeters19 decimeters to to millimetersmillimeters:: Move the decimal Move the decimal 2 2 places to the places to the RIGHTRIGHT:: 1900 millimeters1900 millimeters

Convert Convert 1378 g1378 g to to kgkg:: Move the decimalMove the decimal 33 places to the places to the LEFTLEFT:: 1.378 kg1.378 kg

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USCS - Metric  ConversionsUSCS to Metric Metric to USCSMetric to USCS

1 in. = 2.540 cm1 in. = 2.540 cm 1 cm = 0.3937 in.

1 ft = 0.3048 m1 ft = 0.3048 m 1 m = 3.28 ft

1 yd = 0.9144 m 1 yd = 0.9144 m 1 m = 1.094 yd

1 mi = 1.6093 km1 mi = 1.6093 km 1 km = 0.6214 mi

1 lb = 0.4536 kg1 lb = 0.4536 kg 1 kg = 2.205 lb

1 fl oz = 29.574 1 fl oz = 29.574 mLmL

1 mL = 0.03381 fl oz

1 qt = 0.9464 L1 qt = 0.9464 L 1 L = 1.057 qt

1 gal = 3.785 L1 gal = 3.785 L 1 L = 0.2642 gal

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Conversions between Metric and USCS

Convert 20 gallons to liters.

3.78520

1

Litersgal

gal

75.7Liters

Conversions between Metric and USCS

Convert 105 centimeters to yards.

. 1 1 1105

2.54 12 3

in ft ydcm

cm in ft

1.148yd

Temperature UnitsTemperature Units

FahrenheitFahrenheit Water freezes at 32Water freezes at 32ºF, boils at 212ºFºF, boils at 212ºF

CelsiusCelsius Water freezes at 0Water freezes at 0ºC, boils at 100ºCºC, boils at 100ºC

KelvinKelvin Water freezes at 273.15K, boils at Water freezes at 273.15K, boils at

373.15K373.15K Coldest known temperature = 0 KelvinColdest known temperature = 0 Kelvin(-459.67(-459.67ºF = -273.15ºC)ºF = -273.15ºC)

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Converting TemperaturesConverting Temperaturespage 107page 107

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To Convert from Conversion Formula

Celsius to Fahrenheit  

F = 1.8C + 32

Fahrenheit to Celsius

C = (F-32)/1.8

Celsius to Kelvin K = C + 273.15

Kelvin to Celsius C = K - 273.15

You tryYou try A ‘normal’ human temperature is A ‘normal’ human temperature is

98.698.6ºF What is that in Celsius, ºF What is that in Celsius, and Kelvin?and Kelvin?

K C 273.15

F 32C

1.8

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98.6-32 66.6

1.8 1.8 37 C

K 37 273.15 310.15K

Question?Question?

A local weather report says that A local weather report says that tomorrow’s high temperature will be 52tomorrow’s high temperature will be 52º, º, but does not specify whether the units are but does not specify whether the units are Fahrenheit or Celsius. Fahrenheit or Celsius.

Can you tell which it is? How?Can you tell which it is? How?

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1.8 32

1.8(52) 32 125.6

F C

Energy and PowerEnergy and Power

EnergyEnergy is what makes matter move or is what makes matter move or heat up. The international metric unit of heat up. The international metric unit of energy is the energy is the joulejoule. .

PowerPower is theis the raterate at which energy is used. at which energy is used. The international metric unit of power is The international metric unit of power is the the wattwatt, defined as, defined as

joule

1 watt 1second

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Energy & PowerEnergy & Power

A A kilowatt-hourkilowatt-hour is a unit of energy: is a unit of energy: 1 kilowatt-hour = 3.6 million joules1 kilowatt-hour = 3.6 million joules

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1000 60sec 60minsec 1min 11 1 1joules

hrKW hr hr

According to my electric bill my total According to my electric bill my total electrical energy usage during the electrical energy usage during the past 12 months was 19,227 KWH.past 12 months was 19,227 KWH.

And, I was charged (roughly) And, I was charged (roughly) $.032/KWH.$.032/KWH.

How much did I spent on power in the How much did I spent on power in the last year?last year?

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$.032

19227 KHW $615.261KWH

Units of Density/ConcentrationUnits of Density/Concentration

Density Density – describes compactness or – describes compactness or crowding.crowding. g/cmg/cm33, people/mi, people/mi22

ConcentrationConcentration describes the amount describes the amount of one substance mixed with of one substance mixed with another.another. ppm, g/100mL (BAC)ppm, g/100mL (BAC)

• For most states – legal limit is 0.08g/100mLFor most states – legal limit is 0.08g/100mL

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ExampleExample Manhattan Island has a population of Manhattan Island has a population of ≈ 1.5 ≈ 1.5

million people living in an area of about 57 million people living in an area of about 57 kmkm22. What is its population density? How . What is its population density? How much space is available per person?much space is available per person?

2

1,500,000people

57 km

people

densityarea

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2

people

km26,000

ExampleExample How much space is that per person?How much space is that per person?

Which is roughly 6mWhich is roughly 6m×6m, or 20ft × 20 ft.×6m, or 20ft × 20 ft.

21km

26,000people

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2

2

1km 1000m 1000m

26,000people 1km 1km

38m /person

ExampleExample An average-sized man has about 5L of An average-sized man has about 5L of

blood, and an average 12-ounce beer blood, and an average 12-ounce beer contains 15g of alcohol. If all the alcohol contains 15g of alcohol. If all the alcohol were immediately absorbed into the were immediately absorbed into the bloodstream, what would his BAC be?bloodstream, what would his BAC be?

g

.003mL

15g alcohol 15g alcohol

5L 5000mL bloodconcentration

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g100mL100mL 100mL.003 0.3

More Practice

A boat is moving at 30 knots (nautical miles per hour). How fast is this in miles per hour?

30 6076.1 1

1 5280

knots ft mile

hr knot

34.52mph

More Practice

Eight ounces of hard liquor typically contain about 70g of alcohol. Consider a 200lb man, with approx. 6 liters of blood, who quickly drinks 8 oz. of hard liquor. If all the alcohol were immediately absorbed into his bloodstream, what would his BAC be?

70 70.0116

6 6000gmL

g g

L mL

100.0116 1.16

100 100gmL

mL g

mL mL

More Practice

Now assume his body eliminates the alcohol through metabolism at the rate of 15g/hr. What is his BAC 4 hours after drinking the liquor? Is it safe for him to drive at this time?

10 100.0016 0.16

6000 100 100

g g mL g

mL mL mL mL

15Eliminates 4 60

ghr g

hr

70 60 10g g g

Homework for WednesdayHomework for Wednesday

Pages 113-117Pages 113-117

# 14, 40, 58, 60a,b,c, 71, 73, 94# 14, 40, 58, 60a,b,c, 71, 73, 94

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